Microelectromechanical systems (MEMS) are critical devices for various highly sensitive applications. For example, MEMS include navigation and guidance control devices for advanced smart munitions/missile systems. However, the development and potential fielding of these next generation smart systems is currently impeded by the inability to satisfy the stringent performance standards for the precision and control of their “target-hit interactions”. These advanced smart systems currently suffer from severe inaccuracies caused by a critical failure of a MEMS inertial measurement unit (IMU), i.e., the angular rate sensor (ARS). This IMU failure is caused by its susceptibility to a harsh extrinsic vibration environment. This environment, generated from launch, high-G, and/or in-flight vibration forces, causes an out-of-plane motion or false angular rate signal to be generated. Specifically, inertial MEMS devices work by deriving positional information from measured acceleration and time. Acceleration sensors typically employ minute cantilevered rest masses mechanically resonating in a given plane. The angular rate sensors required for these smart systems work by measuring the relative motion of a resonating beam out from the plane of resonance (resonant frequency ranging from 8 kHz to 25 kHz). The Coriolis acceleration has to be accounted for any moving body in a rotating reference frame, i.e., the earth. This motion is proportional to the angular rotation of the device and is sensed with respect to the package. The derived positional information is therefore dependent on the accuracy of such input data. An out-of-plane motion (therefore, an angular rate) that is generated by erroneous vibrations at or near the resonant frequency of the beam structure will give false angular signals, causing decreased accuracy of the target-hit interactions. Clearly, vibration damping of the MEMS-ARS is needed for successful guidance and navigational control of propellant and/or gun launched projectiles.
Thus, there is a continuing need for vibration damping apparatus, particularly in MEMS devices, as well as methods for fabrication of vibration damping devices.